An optical interface was incorporated into a three channel telemetry device to allow for communication to a packaged telemeter. Information transmitted on the optical link includes calibration parameters and commands to program the operation of the telemeter. The optical ink allows calibration information to be programmed into a telemeter, without the need for a bio-compatible electrical connection. The optical link was designed to completely reside on an integrated circuit chip. One of the three channels of the telemeter is dedicated to temperature measurement, while the other two channels are generic. The generic channels carry information from transducers that are interfaced to the system through on-chip general purpose operational amplifiers. The calibration information that is programmed into the telemeter is retrieved by time division multiplexing it with one of the generic channels.

The historically high toll in human lives lost to natural disasters such as hurricanes, tornadoes, floods, and other progressive events signals the need for some type of personal warning that alerts people to the need to evacuate or otherwise protect themselves in the face of an advancing threat. Traditional warning services, which rely on broadcasts by the mass media in the metropolitan areas of the United States, achieve measurable success in disseminating warnings. However, warnings to isolated populations that exist in the U.S. and elsewhere in the world may be poor to effectively nonexistent, especially in the many archipelagoes. Earth Alert, a joint project of NASA Goddard Space Flight Center and Scientific and Commercial Systems Corporation, is targeted at development of a simple, low-cost means for providing timely warning to otherwise isolated populations. The project uses appropriate relay capabilities of U.S. satellites already in orbit, and thus avoids the high-cost development and launch of dedicated resources.

Under the direction of the NASA George C. Marshall Space Flight Center, Huntsville, Alabama, the development and commercialization of an advanced Automated Part Identification (API) system is being undertaken by the Rockwell Aerospace Division. The new API system is based on a variable sized, machine-readable, matrix symbol that can be applied directly onto most metallic and nonmetallic materials using safe, permanent marking methods. Its checkerboard-like structure is the most space efficient of all symbologies. This high data- density symbology can be applied to products of different material sizes and geometries using application-dependent, computer-driven marking devices. The high fidelity markings produced by these devices can then be captured using a camera linked to a IBM-compatible microcomputer. Application of Compressed Symbology technology will reduce costs and improve quality, productivity, and processes in a wide variety of federal and commercial applications.

A dual lumen catheter (1.19 mm O.D.) was used as the basis for an in-vivo ion selective electrode with telemetric readout. The two lumens were used respectively as working and reference chambers. The reference chamber has a hole contacting the external medium, and the working electrode chamber has a hole contacting the ion selective membrane. The internal electrolytes for both chambers were gelled, and their compositions were optimized for extended lifetime and stability. The catheter has been interfaced to a 450 kHz amplitude- modulated implantable telemetry transmitter which incorporates a high impedance (> 10¹² ohm) preamplifier and allows for nearly continuous measurement of pH and temperature. To avoid both probe contamination and blood clotting, we are currently implementing a self-cleaning membrane system. The results shown will pertain to a pH in-vivo probe.

For the imaging of X-rays and gamma-rays above the energy of about 10 keV (wavelength shorter than 0.12 nanometer) lenses or mirrors cannot be used. For future X-ray and gamma- ray imaging instruments, configurations of patterns of slits and detectors are proposed where, with the help of Fourier analyses of the observed temporal and spatial radiation modulation, images can be composed with a spatial resolution in the arcsecond domain. The patterns of slits, called `grids', are difficult to realize because of the small slit width and the severe requirements on the slit position, given the required thickness of the material. Now these patterns of slits can be made, it has sense to investigate what other instruments or products could make use of this grid manufacturing technique. First of all, this paper describes in short the method of grid manufacturing dealt with here and the most significant characteristics of these grids. The technique allows for the manufacturing of similar grids, with other slit width, slit mutual distance, slit viewing direction, etc. The second part of this paper suggests some possible applications of grids that could be made with the same technique, for the field of medicine, crystallography and other fields. These suggestions may initiate other applications, not yet thought of.

The first lidar system to employ a holographic optical element as the receiver telescope and scanning mirror has been developed to measure cloud and aerosols from a ground based platform with the primary objective of demonstrating technology that offers the advantage of decreased system complexity, size and weight so that satellite based lidar systems can be made smaller, lighter, and cheaper.

Fiber optic interferometric sensors have been developed to provide real time measurement of structural vibrations. One immediate application is the measurement of vibrations on space structures. The detected vibration signals can be applied to a control system which activates appropriate actuators to dampen vibrations. In this work, optical fibers are arranged in a Michelson interferometer configuration in which one the interferometer arms is placed on the vibrating structure and other arm serves as the reference. As the structure vibrates, the fiber is strained and results in a change in phase of the light with respect to the reference arm. Necessary electronic circuits are developed to detect the induced phase changes. These circuits could be used for other kinds of fiber optic sensors such as pressure and temperature sensing, accurate positioning systems, and rotating sensing. The sensor is tested on a laboratory model of a space truss structure and an optical matrix-vector multiplier is used as the controller. In this paper the details of the sensor and experimental results will be presented.

This paper addresses two fiber optic sensor development programs in the Photonics Laboratory, NASA Ames Research Center, one in progress and the other being initiated. The ongoing program involves development of advanced acoustic sensors for wind tunnel applications. The new undertaking involves development of a novel sensor technique for studies of aerodynamic transition from laminar to turbulent flow.

Thin film thermocouples provide a minimally intrusive means of measuring surface temperature in hostile, high temperature environments. Unlike wire thermocouples, thin films do not necessitate any machining of the surface, thereby leaving intact its structural integrity. Thin films are many orders of magnitude thinner than wire, resulting in less disruption to the gas flow and thermal patterns that exist in the operating environment. Thin film thermocouples have been developed for surface temperature measurement on a variety of engine materials. The sensors are fabricated in the NASA Lewis Research Center's Thin Film Sensor Lab, which is a Class 1000 Clean Room. The thermocouples are platinum-13% rhodium vs platinum and are fabricated by the sputtering process. Thin film-to-leadwire connections are made using the parallel-gap welding process. Thermocouples have been developed for use on superalloys, ceramics and ceramic composites, and intermetallics. Some applications of thin film thermocouples are: temperature measurement of Space Shuttle Main Engine turbine blade materials, temperature measurement in gas turbine engine testing of advanced materials, and temperature and heat flux measurements in a diesel engine. Fabrication of thin film thermocouples is described. Sensor durability, drift rate, and maximum temperature capabilities are addressed.

Leaks on the Space Shuttle while on the Launch Pad have generated interest in hydrogen leak monitoring technology. An effective leak monitoring system requires reliable hydrogen sensors, hardware, and software to monitor the sensors. The system should process the sensor outputs and provide real-time leak monitoring information to the operator. This paper discusses the progress in developing such a complete leak monitoring system. Advanced microfabricated hydrogen sensors are being fabricated at Case Western Reserve University (CWRU) and tested at NASA Lewis Research Center (LeRC) and Gencorp Aerojet (Aerojet). Changes in the hydrogen concentrations are detected using a PdAg on silicon Schottky diode structure. Sensor temperature control is achieved with a temperature sensor and heater fabricated onto the sensor chip. Results of the characterization of these sensors are presented. These sensors can detect low concentrations of hydrogen in inert environments with high sensitivity and quick response time. Aerojet is developing the hardware and software for a multipoint leak monitoring system designed to provide leak source and magnitude information in real time. The monitoring system processes data from the hydrogen sensors and presents the operator with a visual indication of the leak location and magnitude. Work has commenced on integrating the NASA LeRC-CWRU hydrogen sensors with the Aerojet designed monitoring system. Although the leak monitoring system was designed for hydrogen propulsion systems, the possible applications of this monitoring system are wide ranged. Possible commercialization of the system will also be discussed.

Sensors 2000! (S2K!) is a specialized, high performance workgroup primarily organized to provide focused, directed, advanced biosensor and bioinstrumentation systems technology in support of NASA's life sciences spaceflight and ground-based research and development programs. A concurrent objective is to promote the mutual use, application, and transition of developed technology by collaborating in academiccommercial-government leveraging, joint research, technology utilization and commercialization, and strategic partnering alliances.

The Houston Advanced Research Center and the National Aeronautics and Space Administration, Goddard Space Flight Center, Technology Utilization Office have recently miniaturized an Airborne LIDAR Topographic Mapping System (ALTMS) and begun to economically collect accurate data from a commercial, photogrammetry based aircraft. This ALTMS incorporates off-the-shelf state-of-the-art laser and new computerized data acquisition technology to record and process digital topographic data. A color video camera collects tandem imagery. This paper describes the first products that have been generated from ALTMS data. Numerous government agency and industry pilot projects are being scheduled and the ALTMS is soon to be offered as a commercial system and service in the very near future.

Bi-directional reflectance from earth terrain surfaces, particularly vegetation has placed increasing emphasis on the measurement of angular reflectance. Many remote-sensing scientists today are focusing on measurements and/or modeling of the angular reflectance properties of earth surface materials. The angular studies emphasis is occurring for several reasons. Of the four primary aspects of land surface reflectance (i.e., spectral, spatial, temporal, angular), this is the least intensively studied and, therefore, the least understood. The angular reflectance properties of Earth targets and, in particular, the bi-directional reflectance of land surface cover types, must be studied to develop algorithms to provide more accurate estimates of spectral hemispherical reflectance and albedo, which is a crucial input to Global Climate Models. The maximum potential of current satellites (e.g., SPOT, AVHRR) that acquire off-nadir viewing data cannot be realized without a good understanding of the angular reflectance properties of the Earth's surfaces. Future EOS satellite instruments (e.g., MISR) have been included expressly to take advantage of, or, to help overcome, the Earth's surface and atmosphere angular reflectance dependencies. The PARABOLA II field scanning radiometer will aid in ground calibration.

Engineers at NASA's Kennedy Space Center have designed a signal conditioning amplifier which automatically matched itself to almost any kind of transducer. The product, called Universal Signal Conditioning Amplifier (USCA), uses state-of-the-art technologies to deliver high accuracy measurements. USCA's features which can be either programmable or automated include: voltage, current, or pulsed excitation, unlimited resolution gain, digital filtering and both analog and digital output. USCA will be used at Kennedy Space Center's launch pads for environmental measurements such as vibrations, strains, temperatures and overpressures. USCA is presently being commercialized through a co-funded agreement between NASA, the State of Florida, and Loral Test and Information Systems, Inc.

Automated welding technology and techniques for welding advanced aluminum alloys with potential for industrial and commercial applications have been developed by the National Aeronautics and Space Administration at the Marshall Space Flight Center. These technologies are being offered to private companies for commercial development, and include: Variable polarity plasma arc welding, a welding process that produces high-quality aluminum welds for fabrication of the space shuttle external tank and space station common module structures. This process uses reverse polarity pulses to produce welds virtually free of internal defects. Advanced weld sensor technology, comprised of machine vision-based weld seam tracking that uses both structured and global laser illumination for finding weld joints, even those difficult to discern by the human eye. Weld pool feedback is accomplished with a vision system to measure arc symmetry and molten weld pool geometry. A weld bead profiler trails the welding torch. It provides feedback to the process control system, which records quality control data.

The Advanced Computed Tomography Inspection System (ACTIS) was developed by the Marshall Space Flight Center to support in-house solid propulsion test programs. ACTIS represents a significant advance in state-of-the-art inspection systems. Its flexibility and superior technical performance have made ACTIS very popular, both within and outside the aerospace community. Through Technology Utilization efforts, ACTIS has been applied to inspection problems in commercial aerospace, lumber, automotive, and nuclear waste disposal industries. ACTIS has even been used to inspect items of historical interest. ACTIS has consistently produced valuable results, providing information which was unattainable through conventional inspection methods. Although many successes have already been demonstrated, the full potential of ACTIS has not yet been realized. It is currently being applied in the commercial aerospace industry by Boeing Aerospace Company. Smaller systems, based on ACTIS technology are becoming increasingly available. This technology has much to offer small businesses and industry, especially in identifying design and process problems early in the product development cycle to prevent defects. Several options are available to businesses interested in pursuing this technology.

This paper describes a variety of practical application circuits based on the current loop signal conditioning paradigm. Equations defining the circuit response are also provided. The constant current loop is a fundamental signal conditioning circuit concept that can be implemented in a variety of configurations for resistance-based transducers, such as strain gages and resistance temperature devices. The circuit features signal conditioning outputs which are unaffected by extremely large variations in lead wire resistance, direct current frequency response, and inherent linearity with respect to resistance change. Sensitivity of this circuit is double that of a Wheatstone bridge circuit. Electrical output is zero for resistance change equals zero. The same excitation and output sense wires can serve multiple transducers. More application arrangements are possible with constant current loop signal conditioning than with the Wheatstone bridge.

A Real-Time Instrument for the detection of non-volatile residues (NVR) was developed under an SBIR Phase I contract for the NASA Contamination Monitoring Laboratory at Kennedy Space Center (KSC) in Florida. A prototype device was fabricated and field tested in the Operations and Checkout Building and at the Orbiter Processing Facility at KSC. During the field testing, the data from the instrument was compared to standard KSC non-volatile residue measurements which are based on ASTM 1234/1235. Time fluctuations, unique to the real time measurement process, were also correlated to activity logs for the facility. The prototype instrument has already been applied commercially in the semiconductor industry to study NVR contamination in the plastic boats that wafers are stored and transported in during processing. This technology is being evaluated for use in the Hubble Space Telescope refurbishment mission to monitor NVR deposition during integration and processing prior to launch. This paper will discuss the temperature controlled SAW NVR instrument development program as well as the field testing done at KSC. Application to measurements of non-volatile residue in operational environments and comparisons with KSC NVR measurements will be made.

During flight hardware processing at Kennedy Space Center, all critical surfaces are inspected for flaws such as scratches, gouges, raised metal and corrosion pitting. Key dimension of defects (maximum depth, width and length) are measured by one of two methods: mold impression/optical comparator system or optical micrometry. The configuration of the flaw (shape factor, surface material, etc.) determines which technique to use. Both of these techniques have inherent problems, primarily in speed, reliability and the ability to record permanently the actual data taken. The processing of flight hardware dictates the need for an improved method. Tight schedules require quick, reliable and permanent measurements to allow engineering to disposition the problems and resume processing. After an unsuccessful search of the market for a suitable instrument, NASA requested that an instrument be developed to replace the current methods. The I-NET Space Services Special Instrumentation Laboratory, as a contractor to NASA, was tasked with the project. The technique chosen for prototyping a working instrument was structured light microscopy, also referred to as light section microscopy. A prototype was developed and is presently being evaluated by the potential users for implementation as operational Space Shuttle ground support equipment. A description of the instrument and its subsystems, as well as the status and future plans, are presented.

An integrated optoelectronic receiver has been developed for Monolithic Microwave Integrated Circuit (MMIC)-based phased array antenna applications. The device enables the distribution of MMIC control signals, necessary for the steering of the antenna, by fiber optics rather than electrical cables. This method of control signal distribution minimizes the weight of the antenna system, and virtually eliminates any electromagnetic interference. Additionally, the fiber optic cable greatly improves the mechanical flexibility of routing the control signals. The Monolithic Optical REceiver (MORE) was developed under contract with Honeywell. The device features fully monolithic integration of a photodetector, a low noise amplifier, and a digital demultiplexer on a GaAs substrate. The MORE can operate at user-selectable data reception rates ranging from 10 to 400 Mbps, has built-in clock recovery, and is addressable. The MORE can also be operated in a continuous reception mode or data can be sent in a bursted mode. This paper will describe the features of the MORE and the applications for which it is already being used in both space and terrestrial applications.

Imaging x-ray microscopes currently under development at the Marshall Space Flight Center utilize multilayer x-ray/EUV optical systems and structural components similar to those developed for normal incidence imaging solar x-ray telescopes. The Water Window Imaging X-Ray Microscope is specifically designed to operate at x-ray wavelengths within the `water window' regime, wherein water is relatively transmissive and carbon is highly absorptive. This important natural property of the interaction of x-rays with matter should permit this microscope to sharply delineate carbon based structures within living cells. The ability to image living cells in aqueous physiological environments, with high spatial resolution and high contrast, may afford advantages not available with conventional microscopes and make possible non-invasive strategies for examining living tumor cells without the need of stains or exogeneous chemicals that can produce limiting artifacts. The Water Window Imaging X-Ray Microscope represents a `spinoff' of multilayer x-ray telescope technology. This paper reviews the multilayer x-ray telescope developments which led to this x-ray microscope research. It considers the design, fabrication, optical assembly, alignment, and testing of the prototype microscopes and provides the results of recent studies of ultrahigh resolution photographic films and the design of high reflectivity multilayer coatings for applications in the water window.

The Small Business Innovation Research (SBIR) Program was established by Congress in 1982 through the Small Business Innovation Development Act. The SBIR Program is currently authorized through the year 2000. The objectives ofthe SBIR Program include stimulating technological innovation in the private sector, strengthening the role of small business concerns in meeting federal research and development needs, increasing the commercial application of federally supported research results, and fostering and encouraging participation by socially and economically disadvantaged persons and women-owned small businesses in technological innovation. The SBIR Program is open to American-owned companies with less than 500 employees. It is a three phase program with Phase I being a six (6) months feasibility phase for a maximum of $100,000; Phase II being the development phase for twenty-four (24) months for a maximum of $750,000; and Phase ifi being the commercial phase where the company markets the developed technology through the use of private (nongovemment) funds.

Because each federal laboratory is unique in makeup and mission, each of us approaches the challenge of commercializing our technologies in a unique way. Sharing these unique procedures, as well as successful and unsuccessful transfer experiences, with one another can give us new insights into our own problems and challenges. This paper will discuss the technology commercialization processes used at the NASA Lewis Research Center. It will focus on experiences and strategies that suggest ways to deal with challenges brought on by the changing federal research environment. One such challenge is finding new sources to fund projects that develop the `bridging technologies' necessary to convert the aerospace technology to commercial technology.